The author analyzes states' success in covering their uninsured citizens. Nationwide in 1997, the insurance gap, defined as the share of a state's non-elderly adult residents who would be uninsured in the absence of public insurance coverage, was 21 percent. Of the 13 states studied, the insurance gap ranged from 30.4 percent in Texas to 12.2 percent in Wisconsin. States with limited public insurance programs generally covered the smallest proportion of their insurance gap for all income groups. On average, states with comprehensive programs covered twice the proportion of their insurance gap for low-income adults relative to limited program states. Even in comprehensive program states a substantial proportion of low income adults who lacked other insurance were not reached by public coverage.